The world’s population will climb to 9.7 billion in 2050, and India’s population is projected to overtake that of China, while some of the African countries with higher fertility rates will see their population doubling during the period, a new study said Wednesday.

According to a bi-annual report by the French Institute of Demographic Studies, or Ined, the world population is expected to grow to 10 billion to 11 billion people by the end of the 21st century, from its current level of 7.1 billion.

The report authored by Gilles Pison, director of research at Ined, said that two Asian giants, China and India, will swap their current respective positions as the world’s most populous country and the second-most populous country, by 2050.

India’s population will rise to 1.6 billion by 2050, from its current level of 1.2 billion, while the Chinese population is projected to remain unchanged at its current level of 1.3 billion, during the period.

The findings of the study are in line with the projections made by a U.N. study, released in June, which pegged the world population to reach 9.6 billion by 2050. According to the U.N. report, total population in developed nations will remain at around 1.3 billion from now until the middle of the century, but in 49 of the world's least-developed countries, the population is projected to double to 1.8 billion by 2050 from around 900 million in 2013.

According to Pison, Africa will see exponential growth in its population, and the continent is expected to be home to 2.5 billion people – a fourth of the total world population – by 2050, from its current population of about 1.1 billion.

Pison attributed the population growth to a high fertility rate in Africa, which at 4.8 children per woman now, is almost twice the global average of 2.5 children per woman. According to the report, Nigeria, the most populous nations in Africa, is expected to have a population of 444 million, which will exceed the projected U.S. population of 400 million, by 2050.

Meanwhile, the population in the Americas is expected to touch 1.2 billion, by the middle of the century from the current 4.3 billion, and Asia’s population is projected to breach the 5 billion mark in 2050, from its current level 4.3 billion, the report said.